The Mill Is Peppered With Problems

The peppermill that resides on our kitchen table was on its last legs, so my wife bought me a new one for Christmas. It seemed reasonably well made, had an adjustment for how fine it ground the pepper, and even had the grinder at the top so it didnít leave a mess wherever it sat. I was a little concerned that the grinding surfaces were plastic, but Iíve learned over the years that well-chosen polymers donít necessarily mean cheap. A couple of days later, it stopped grinding -- OK, maybe it was cheap after all.

Now that I had two barely functional peppermills, I did what any engineer with four kids would do -- I set them aside for some time when I could figure out what was going on. A couple of months later, having exhausted the supply of pre-ground pepper in the house, the time had come for a design review. I carefully disassembled the peppermill and examined its components. It was set up as a ratcheting design, where the grinding rotor (white) was rotated by engaging teeth on a driver (black square).

A close-up look at the ratcheting surfaces of the peppermill.

The square driver was inside a square recess, which was driven by the outside of the mill, held by the user. A curved disk spring pressed the square driver against the grinder. The teeth that engage between the driver and grinder were shaped such that they would engage solidly in one direction, but float up and over each other in the other direction, providing a ratcheting action so that an oscillating rotation of the peppermill body by the user would create a continuous rotation of the grinding surface. The diagnosis was obvious: the spring was not strong enough, allowing the mating teeth to float over one another in both directions, and not turning the grinding surfaces at all.

The first attempt at a solution was to bend the spring, to cause a slightly greater engagement force. After reassembling the peppermill, I found that its behavior had not changed. Only brief contemplation was required to realize that the ratcheting action was a feature I could live without. So I once again dismantled it, and filled the square recess the driver floats in with hot-melt glue, making for a very stiff spring indeed. It no longer ratchets, but it does grind peppercorns just fine. I wonder if the grinding surfaces were touching initially, causing me to damage the form on the engaging teeth on first use, or if there are untold numbers of inoperable peppermills floating around out there. I retained the old one with the metal teeth as a backup in case the plastic grinding surfaces donít last; it will be harder to repair because of accumulated damage from combined fatigue (use) and impact (dropped too many times) damage.

This entry was submitted by James Sebastian and edited by Jennifer Campbell.

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One finds very many pepper mills with ceramic mills, which is orders of magnitude harder than any plastic. I'll go out on a limb, and assume the grinding surfaces aren't plastic, the author glanced at them (white!) and made an assumption, as do you. Alternatively, the grinding surface may have had plastic molded around it.

On that note. I've sat on problems for weeks sometimes. The answer always seems to have a way of finding me. I don't know about the rest of you, but once I have a problem to remedy....I am constantly thinking of solutions. Do they call that a restless mind?

Here is another case where the user drives the mechanism. Since you have kids you cannot have nice things or things that must be used with care and kindness. So for the kids, I'd recommend the disposable grinding mill that comes with McCormick pepper and salt spicejars. And for you, find the Trudeau Graviti grinder. As an engineer you'll appreciate the clever concept of grinder on top and it operates by simply flipping the unit upside down. Though filling it takes some forethought. Only shortfall is it doesn't have built-in illumination as many other battery driven grinders do.

And consider your time in this world. Some things are simply not worthy of your time and effort to disassemble and rehabilitate. Like plastic grinders.

Truer words were never spoken, " I did what any engineer with four kids would do -- I set them aside for some time when I could figure out what was going on."

But as engineers we don't mind spending thousands of dollars in engineering time on products that cost a few dollars. We are driven to it. It is in our nature to get to the bottom of things. Who cares what it costs!

And the way many things are are built, we have gobs of things to work on. This peppermill is just the tip of the iceberg. In these Design News articles we have repaired washing machines, rescue robots, toilets, and Retro Encabulators.

Author, are you sure the grinding surfaces were plastic, and not ceramic? (The ones I have are a white ceramic.) I doubt if even the single use grinders that come with peppercorns in them are plastic, but I'm going to look next chance I get. If they can make a plastic up to this task, I am truly impressed.

I like the idea of the ratcheting action, a pity they didn't get that right. And I love fresh ground pepper. I purchased a number of them over the years before I found the great grinders I now own.

There are a few plastics that perform better than metal in strength and wear properties, but unfortunately thos plastics often cost more than metal. parts. So the challenge is to design for performance and durability rather than minimum price. THE TRICK is to find a way to convince the consumers that the higher priced (whatever) is the item that they want.

WAY too much plastic, especially in heavy or continuous use locations.

All (two - really? 2?!?!) drink holders are broken, necessitating replacing the entire section of the console panel. I won't bother, as they are essentially worthless anyway. Any containr with a C.G. above 3" simply falls off the tray.

Worse, we've gone through three interior door handles. They *look* like chrome plated metal, but are flimsy plastic, guaranteed to break when an unfamiliar rider pulls hard on a locked handle, expecting it to unlock and open the door.

If we value low price over quality, often we end up spending more in the long run. In addition, a grinder on the top of the container may create less mess, but the reason for a grinder in the first place is to have _freshly_ ground pepper. Putting the grinder on the top means that partially ground peppercorns work their way to the bottom and loose their pungency as they sit inside the grinder over time. This results in lower quality ground pepper. That's why I personally prefer the grinder to be on the bottom. I'm willing to put up with the mess to optimize the taste and smell of the pepper.

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